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Contribution of new particle formation to the total aerosol concentration at the high‐altitude site Jungfraujoch (3580 m asl, Switzerland)
Author(s) -
Tröstl Jasmin,
Herrmann Erik,
Frege Carla,
Bianchi Federico,
Molteni Ugo,
Bukowiecki Nicolas,
Hoyle Christopher R.,
Steinbacher Martin,
Weingartner Ernest,
Dommen Josef,
Gysel Martin,
Baltensperger Urs
Publication year - 2016
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1002/2015jd024637
Subject(s) - cloud condensation nuclei , aerosol , atmospheric sciences , entrainment (biomusicology) , troposphere , environmental science , particle (ecology) , particle number , chemistry , meteorology , physics , geology , thermodynamics , oceanography , rhythm , acoustics , volume (thermodynamics)
Previous modeling studies hypothesized that a large fraction of cloud condensation nuclei (CCN) is attributed to new particle formation (NPF) in the free troposphere. Despite the potential importance of this process, only few long‐term observations have been performed to date. Here we present the results of a 12 month campaign of NPF observations at the high‐altitude site Jungfraujoch (JFJ, 3580 m above sea level (asl)). Our results show that NPF significantly adds to the total aerosol concentration at the JFJ and only occurs via previous precursor entrainment from the planetary boundary layer (PBL). Freshly nucleated particles do not directly grow to CCN size (90 nm) within observable time scales (maximum 48 h). The contribution of NPF to the CCN concentration is low within this time frame compared to other sources, such as PBL entrainment of larger particles. A multistep growth mechanism is proposed which allows previously formed Aitken mode particles to add to the CCN concentration. A parametrization is derived to explain formation rates at the JFJ, showing that precursor concentration, PBL influence, and global radiation are the key factors controlling new particle formation at the site.